The field of Systems Biology is beginning to define the complex dynamics of biological regulatory processes. Recently, large-scale protein-protein interaction (PPI) screens have been performed on the TGF-[unreadable] signaling system, revealing a complicated network of hundreds of interacting proteins, many novel. A key question is whether biological processes governed by TGF-[unreadable] signals are regulated by these newfound proteins. TGF-[unreadable] signals govern many important biological processes, but particularly cell differentiation and embryonic development. Therefore, large-scale PPI screens are potentially a rich source of new developmental regulators, but new candidates must be evaluated in an embryonic context. The investigator proposes to use Xenopus embryos to screen new TGF-[unreadable] signaling candidates for developmental activity. His hypothesis is that embryonic functional assays will uncover novel developmental regulators among new interacting proteins emerging from TGF-[unreadable] PPI screens. The approach is to test these proteins for activity in Xenopus embryos by overexpression and gene knockdown. Aim 1 will evaluate the results of published and ongoing PPI screens on the TGF-[unreadable] system to select novel candidates for embryonic tests. Evidence of candidate expression in Xenopus embryos will be initially assessed by EST database searches, or by cDNA cloning. Sequence information will be gathered for genes expressed at neurula or earlier times using EST databases, cDNA cloning, and Xenopus tropicalis genomic information. Aim 2 will perform candidate gene knockdown in embryos with morpholino oligos that block mRNA translation or pre-mRNA splicing. These tests will reveal new developmental regulators and expand our understanding of TGF-[unreadable] signaling and embryogenesis. In broader context, new regulators to be uncovered will inform various fields of new genes that could affect birth defects and diseases through abnormal expression or function, particularly in TGF-[unreadable] signaling. PUBLIC HEALTH RELEVANCE: Growth factor signals, such as those provided by relatives of TGF-[unreadable], govern many important biological processes, such as cell differentiation, embryonic development, wound healing, and tissue/stem cell renewal. The tests proposed in this application will reveal potential functions of new regulators of TGF-[unreadable] signaling during vertebrate embryogenesis. The experiments will point to new genes that might affect human developmental processes, and which might cause birth defects and disease if their activity or expression is abnormal.